def give_max(num=list):
	return max(num)
def solve(num=list):
	n=len(num)
	if n<=2:
		return give_max(num)
	left_list,right_list=num[:n//2],num[n//2:]
	print(left_list,right_list)
	left_max,right_max=solve(left_list),solve(right_list)
	return give_max([left_max,right_max])
	
lis=input('请输入一串无序的数字（每个数之间用“，”隔开）')
lis=lis.replace(',',' ')
lis=list(map(int,lis.split()))

# lis2=','.join(map(str,lis)).split(',')
print(lis)
print(solve(lis))
